A digital subscriber line (DSL, Digital Subscriber Line) is a high-speed data transmission technology on a telephone twisted pair, such as an unshielded twist pair (UTP, Unshielded Twist Pair). A DSL system has multiple DSL lines. At present, a DSL access multiplexer (DSLAM, Digital Subscriber Line Access Multiplexer) is generally used to provide an access service for the multiple DSL lines. However, due to the electromagnetic induction principle, crosstalk (Crosstalk) may be generated between multiple signals that access the DSLAM. Crosstalk of a twisted pair on a high frequency is very strong. In order to cancel crosstalk, a vectored (Vectored) DSL technology may be used to cancel far-end crosstalk. When the Vectored DSL technology is not used, only 20-30% of an activated rate of a single subscriber line can be reached in most cases. However, if the Vector technology is used, a relatively high rate, even up to 90% of the activated rate of the single subscriber line, can be obtained.
Considering power saving and environment protection, there is a discontinue mode for power saving (Discontinue Mode for Power Saving, DMPS) technology in the DSL field at present. A main idea of the DMPS technology is that when there is no service data, a digital front end (Digital Front End, DFE) processing module, an analog front end (Analog Front End, AFE) processing module, and the like are shut down. The digital front end DFE processing module is, for example, a Fourier transform FFT module or an inverse Fourier transform IFFT module. The analog front end AFE processing module is, for example, a digital-to-analog/digital-to-analog conversion ADC/DAC module or a line driver module. Stopping these modules can reduce power consumption of a system substantially.